1. Field of the Invention
The present invention relates to a machining method and a machining operation for machining a front-end of a laser-beam guiding optical fiber so that the front-end may taper down and a laser beam irradiation device for enabling irradiating a target position with a laser beam by using this optical fiber.
2. Description of the Related Art
In medical treatment, usually, an affected part of the body is irradiated with a laser beam to evaporate an anatomy for treatment or is cut open. A medical device utilizing such a laser beam is configured so that it can guide a laser beam emitted from a laser oscillator to an affected part of the body and irradiate the affected part with the laser beam through a probe. The probe is made of a material which a laser beam can pass through and has its top portion extremely tapered so that when this front-end is brought close to or into contact with a target affected portion of the body, the affected part can be irradiated with the laser beam.
If a laser beam to be utilized can be guided thorough an optical fiber, the probe is provided to a front-end of the optical fiber. The probe is formed by grinding quartz, sapphire, etc. so that it may comprise a tapered end and a mounting portion for the optical fiber. Further, the probe may come in contact with a body fluid of a patient and so needs to be sterilized indispensably, so that it may be necessary to reserve a lot of such probes.
Such probes made of quartz or sapphire have a problem that they may fluctuate in shape and size and so be destabilized and a cost-related problem because it takes a lot of time to machine them and a lot of such probes needs to be used. To solve these problems, recently a front-end of an optical fiber is tapered to use the optical fiber as a probe.
According to such a method for tapering a front-end of an optical fiber, when performing chemical etching on one end of a probe material in a condition where the end is soaked in an etchant, a fluid level of the etchant with respect to the probe material is moved at a predetermined speed (see, for example, Patent Literature 1). Further, such a method is proposed that a probe may be formed by mechanically grinding a front-end of an optical fiber in such a manner that a core portion may be a cutting edge and soaking this end into an etchant so that it may be sharp (see, for example, Patent Literature 2).
Patent Literature 1: Japanese Patent Application Laid-Open (JP-A) No. 07-218516
Patent Literature 2: JP-A No. 2004-12427